package cc.coopersoft.keycloak.phone.providers.sender;

import java.security.MessageDigest;

public class CheckSumBuilder {

  // 计算并获取CheckSum
  public static String getCheckSum(String appSecret, String nonce, String curTime) {
    return encode("sha1", appSecret + nonce + curTime);
  }

  // 计算并获取md5值
  public static String getMD5(String requestBody) {
    return encode("md5", requestBody);
  }

  private static String encode(String algorithm, String value) {
    if (value == null) {
      return null;
    }
    try {
      MessageDigest messageDigest
              = MessageDigest.getInstance(algorithm);
      messageDigest.update(value.getBytes());
      return getFormattedText(messageDigest.digest());
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
  }

  private static String getFormattedText(byte[] bytes) {
    int len = bytes.length;
    StringBuilder buf = new StringBuilder(len * 2);
    for (int j = 0; j < len; j++) {
      buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
      buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
    }
    return buf.toString();
  }

  private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5',
          '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
}
